Presenter's name: Igor Sokolov, Ph.D.

1. U-dots for unique security tagging Presenter's name: Igor Sokolov, Ph.D. Organization affiliation: NanoScience Solutions and Tufts University Telephone number: 315-212-4865, 617-627-2548 Email address: cto@NanoScienceSolutions.com; igor.sokolov@tufts.edu

2. Idea: fluorescent labeling Labeling with special fluorescent particles: U-dots® Complex fluorescent spectra that do not exist naturally

3. U-dots: Technology U-dots are silica nanoporous particles in which existing (including commercial) fluorescence dyes are encapsulated inside the pores/channels U-dots can be Micron-nano size 2-5 micron particles 60 nm particle 25 nm particle U-dots sizes can be between 8 nm and tens of microns

4. 10 nm U-dots: Technology All have cylindrical pores of nanosize diameter: Micron particles Nano particles

5. U-dots: Brightness Brightness of 40 nm particles relative to 1 molecule of R6G dye and quantum dots (CdSe/ZnS green) dye U-dots Q-dot

6. U-dots Comparison with Q-dots and other fluorescent particles

7. U-dots Comparison with Q-dots and other fluorescent particles

8. U-dots for color encoding Example of fluorescence of micron U-dots containing various dyes and their mixes Physical mix of 4 different dye compositions

9. U-dots: high stability Photobleaching A relative decrease of brightness of different fluorescent substances compared to fluorescent nanoporous silica nanoparticles (FSNP). 25 mW 488 nm laser in a scanning confocal microscope was utilized. Long-term stability without intensive photobleaching: So far the spectral stability of R6G dye encapsulated in micron-size U-dots was tested evaluated. It was stable after 7 years of storage in ambient conditions in water. It is expected to be save for much longer in air or encapsulated.

10. How many different combinations? • The total number comes from MULTIPLICATION of number from the following 3 categories: • Dyes with different spectra (~200) and their combinations: assuming 4 dyes: ~65,000,000assuming 3 dyes: ~1,300,000assuming 2 dyes: ~20,000 • Different relative concentrations of dyes (~5-10 for 2 dyes, 25-100for 3 dyes, 125-1000for 4 dyes). • Different spectra at different excitation wavelengths (~5-10)

11. Example of Different relative concentrations of dyes Fluorescence spectra of particles encapsulating two fluorescent dyes at molar ratios of a)10 b)20 c)50 d)70 e)90

12. Example of spectral reading Algorithm • Unambiguous solution if spectra are sufficiently different in the entirespectral range (the determinant of the Gaussian matrix of the linear equation is not equal to zero). The particles with the entirely overlapped spectra can still be reliably resolved.

13. Technology readiness and unsolved problems • The technology for U-dots is ready. NNS holds the exclusive license from Clarkson University for ultrabright fluorescent particles. Dr. Sokolov developed this technology while in the Department of Physics and Chemical and Biomolecular Sciences with a partial support from the US Army research office. • The problems still to be answered: • Packaging of U-dots for security labeling applications. • Spectral stability of packaged U-dots (though expected to be high) has to be studied. • Incorporation of multiple dyes: non-linear effects of the concentration are to be investigated. This may add more multiplexing but it could be more subject to spectral change with time..

14. References • Papers: • Palantavida, S., Guz, N. V., Woodworth, C. D. & Sokolov, I. Ultrabright fluorescent mesoporous silica nanoparticles for prescreening of cervical cancer. Nanomedicine, (2013). • Palantavida, S., Guz, N. V. & Sokolov, I. Functionalized Ultrabright Fluorescent Mesoporous Silica Nanoparticles. Part PartSyst Char30, 804-811, (2013). • Volkov, D. O., Cho, E. B. & Sokolov, I. Synthesis of ultrabright nanoporous fluorescent silica discoids using an inorganic silica precursor. Nanoscale3, 2036-2043, (2011). • Cho, E. B., Volkov, D. O. & Sokolov, I. Ultrabright Fluorescent Silica Mesoporous Silica Nanoparticles: Control of Particle Size and Dye Loading. Advanced Functional Materials21, 3129-3135, (2011). • Sokolov, I. & Volkov, D. O. Ultrabright fluorescent mesoporous silica particles. Journal of Materials Chemistry20, 4247–4250, (2010). • Cho, E. B., Volkov, D. O. & Sokolov, I. Ultrabright Fluorescent Mesoporous Silica Nanoparticles. Small6, 2314-2319, (2010). • Sokolov, I. & Naik, S. Novel fluorescent silica nanoparticles: towards ultrabright silica nanoparticles. Small4, 934-939, (2008). • Sokolov, I., Kievsky, Y., Y & Kaszpurenko, J. M. Self-assembly of ultra-bright fluorescent silica particles. Small3, 419-423, (2007). • Patents: • Igor Sokolov, Shajesh Palantavida “Functionalized ultrabright fluorescent silica particles”, pending 2011 • Igor Sokolov, Eun-Bum Cho, Dmytro Volkov “Syntheses of ultrabright fluorescent silica particles”, pending March 10, 2010 • I. Sokolov, S. Naik, “Syntheses of Ultra-bright Fluorescent Silica Particles”, full patent application filed 2007.